Quibod MNRM, Alviola PAA, de Guia APO, Cuevas VC, Lit IL Jr., Pasion BO. 2019. Diversity and threats to cave-dwelling bats in a small island in the Southern Philippines. Journal of Asia-Pacific Biodiversity (in press). DOI: 10.1016/j.japb.2019.06.001

https://www.sciencedirect.com/science/article/pii/S2287884X18303169

Abstract: More than 2,000 caves have been documented in the Philippines, yet cave research is very limited. Thisstudy was conducted to provide benchmark information on the diversity and ecology of cave-dwellingbats from Samal Island, a small island in the southern Philippines. Bats were surveyed from thirtycaves of varying physical features and disturbances. Fifteen species of bats were identified in the island;14 of which are new records for the island, increasing the island distribution of the identified bats in thecountry. The abundance of cave-dwelling bats varied from low to high density, with some caves esti-mated to harbor more than 10,000 individuals. Abundance and richness of cave-dwelling bats positivelyincreased with longer cave length, higher ceilings, bigger and multiple entrances, and presence of water.The Bat Cave Vulnerability Index (BCVI) revealed three high priority caves,12 medium priority caves and15 low priority caves, indicating the importance of standardized method in assessing cave disturbance.Traces of tourism and hunting were the most common disturbance factors. The results of this studyhighlight the need for fundamental data on the distribution, diversity, and ecology of cave-dweling batsin the Philippines.

Tomlinson KW*, Sterck FJ, Barbosa ERM, de Bie S, Prins HHT, van Langevelde F. Seedling growth of savanna tree species from three continents under grass competition and nutrient limitation in a greenhouse experiment. Journal of Ecology.DOI: 10.1111/1365-2745.13085

https://besjournals.onlinelibrary.wiley.com/doi/abs/10.1111/1365-2745.13085

Abstract: Changes in savanna tree species composition, both within landscapes and across climatic gradients, suggest that species differ in their ability to utilize resources and cope with grass competition. Linking trait variation among species to their relative performance under resource limitation and competition treatments could provide mechanistic understanding of species’ turnover across environmental gradients in savannas. We investigated how tree species differ in response to competition from grasses and nutrient supply, and whether these responses can be related to plant traits. As humid savannas are often associated with low fertility, species of humid savannas may grow more efficiently under nutrient suppression than species from semi-arid savannas. In heterogeneous grass swards, fast-growing, resource-wasteful species may be found in low grass biomass patches and slow-growing, conservative species in high biomass patches. We compared seedlings of 40 tree species sampled from humid and semi-arid savannas of three continents (Africa, Australia, South America) with and without grass competition and with high and low nutrient supply. We measured traits related to soil resource capture, light capture, and growth, and tested whether these traits were related to performance under the four treatments. All tree species were suppressed by grass competition and most by nutrient limitation. Only species from humid savannas in Australia grew better under nutrient limitation than their semi-arid counterparts. Deciduous species from semi-arid climates were more negatively impacted by grass competition than deciduous species from humid climates whereas the reverse pattern was observed among evergreen species. Faster growing species were more severely suppressed by grass competition and low nutrients than slower growing species. Traits associated with soil resource capture and seed mass supported growth under grass competition and nutrient limitation, but the traits differed by continent and by leaf habit. Synthesis. We found limited evidence that tree seedlings from humid savannas grow better under nutrient limitation than species of semi-arid savannas. We confirmed that fast-growing species may be advantaged in low grass biomass patches and conservative species in high biomass patches. Traits that improved performance under grass competition differed by continent, which may relate to differences in leaf habit and constraints on seed size.

Roeder M, Yang W, Tomlinson KW. Influence of smoke, heat and fire on germination of woody species occurring in the dry valleys of southwest China. Journal of Plant Ecology.

https://doi.org/10.1093/jpe/rtz030

Abstract:

Aims

Savannahs depend on fire for their persistence. Fire influences regeneration from seeds in several ways: it converts the environment into a more open space which can benefit the establishment of seedlings, and fire itself can also enhance germination by chemical and physical cues, such as smoke and heat. There is limited information as to how seed of Asian savannah species respond to fire, even though Asia has several dry vegetation types that are associated with fire. Our main question was whether fire enhances or triggers the germination of woody species occurring in southwest Chinese dry valleys, which have savannah vegetation.Methods

We conducted tests with heat (80°C) and smoke solution treatments, and tests with real fire by burning grass on top of sand trays containing seeds. We tested 35 species, including savannah species, and gully and forest species. Depending on seed availability, not all species were tested for all treatments. Twenty-six species had total germination >4% and these were used for analysis.Important Findings

Heat increased germination of three species (strongest reaction: Dodonaea viscosa), smoke increased germination of five species (strongest reaction: Calotropis gigantea). Both treatments decreased germination for five and seven species, respectively. Real fire was detrimental for most species, except for D. viscosa, which is known to respond positively to heat shock. Even though fire-related cues were not a trigger for germination for most species in our study, fire could still be crucial for regeneration by competition release.

Rosialda PBR, Quibod MNRM, Day MD. Preliminary Study on the Distribution of the Introduced Gall-forming Fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae) for the Biological Control of the Invasive Alien Weed Chromolaena odorata (L.) R.M. King & H. Rob. (Asteraceae) in the Philippines. Philippine Journal of Science 148(1): 189-196.

http://philjournalsci.dost.gov.ph/images/pdf/pjs_pdf/vol148no1/preliminary_study_on_the_distribution_of_gall_forming_fly_.pdf

The distribution of Cecidochares connexa (Macquart), a biological control agent of the invasive plant Chromolaena odorata (L.) R.M. King & H. Rob. was determined around the three main islands – Luzon, Visayas, and Mindanao – in the Philippines. A total of 105 sites in 17 localities with C. odorata were surveyed for the presence of C. connexa. Cecidochares connexa was present at 82 sites in eight localities, limited to around Visayas and Mindanao. Some sites where the gall fly was reported were up to 400 km from the initial release sites around Davao, Mindanao. Cecidochares connexa was not found at any of the nine localities surveyed around Luzon. Visual observations showed that the gall fly is having some impact on C. odorata, as evidenced by dead branches and stems. These results show that C. connexa has firmly established in the country and that it has the ability to disperse long distances to new areas. It is likely that C. connexa will continue to disperse further with time. However, a more robust study regarding its presence in other parts of the country and its effectiveness as a biological control agent is needed.

Singh D, Slik FJW, Jeon YS, Tomlinson KW, Yang X-D, Wang J, Porazinska DL, Adams JM. Conversion of Asian tropical forests to monoculture rubber plantation reduces small metazoan α-diversity, and overall diversity. Scientific Reports. DOI: 10.1038/s41598-019-42333-4

Abstract: Tropical rainforests play important roles in carbon sequestration and are hot spots for biodiversity. Tropical forests are being replaced by rubber (Hevea brasiliensis) plantations, causing widespread concern of a crash in biodiversity. Such changes in aboveground vegetation might have stronger impacts on belowground biodiversity. We studied tropical rainforest fragments and derived rubber plantations at a network of sites in Xishuangbanna, China, hypothesizing a major decrease in diversity with conversion to plantations. We used metabarcoding of the 18S rRNA gene and recovered 2313 OTUs, with a total of 449 OTUs shared between the two land-use types. The most abundant phyla detected were Annelida (66.4% reads) followed by arthropods (15.5% reads) and nematodes (8.9% reads). Of these, only annelids were signifcantly more abundant in rubber plantation. Taken together, α- and β-diversity were signifcantly higher in forest than rubber plantation. Soil pH and spatial distance explained a signifcant portion of the variability in phylogenetic community structure for both land-use types. Community assembly was primarily infuenced by stochastic processes. Overall it appears that forest replacement by rubber plantation results in an overall loss and extensive replacement of soil micro- and mesofaunal biodiversity, which should be regarded as an additional aspect of the impact of forest conversion.

Group PI Kyle Tomlinson got the “Yunnan Friendship Award for Foreign Experts 2017”.  Congratulations!

link to report on XTBG webpage:  http://www.xtbg.ac.cn/xwzx/zhxw/201711/t20171121_4897115.html

All 3 CEC Postdocs got NFSC international young scientist award. Congrats!

Ratnam J*, Tomlinson KW*, Rasquinha DN & Sankaran M. 2016. Savannahs in Asia: evidence for antiquity, biogeography, and an uncertain future. Philosophical Transactions of the Royal Society B 371. (*Joint First Author)

http://rstb.royalsocietypublishing.org/content/371/1703/20150305.

Abstract: The savannahs of Asia remain locally unrecognized as distinctive ecosystems, and continue to be viewed as degraded forests or seasonally dry tropical forests. These colonial-era legacies are problematic, because they fail to recognize the unique diversity of Asian savannahs and the critical roles of fire and herbivory maintaining ecosystem health and diversity. In this review, we show: the palaeo-historical evidence suggests that the savannahs of Asia have existed for at least 1 million years, long before widespread landscape modification by humans; savannah regions across Asia have levels of C4 grass endemism and diversity that are consistent with area-based expectations for non-Asian savannahs; there are at least three distinct Asian savannah communities, namely deciduous broadleaf savannahs, deciduous fine-leafed and spiny savannahs and evergreen pine savannahs, with distinct functional ecologies consistent with fire- and herbivory-driven community assembly. Via an analysis of savannah climate domains on other continents, we map the potential extent of savannahs across Asia. We find that the climates of African savannahs provide the closest analogues for those of Asian deciduous savannahs, but that Asian pine savannahs occur in climates different to any of the savannahs in the southern continents. Finally, we review major threats to the persistence of savannahs in Asia, including the mismanagement of fire and herbivory, alien woody encroachment, afforestation policies and future climate uncertainty associated with the changing Asian monsoon. Research agendas that target these issues are urgently needed to manage and conserve these ecosystems.

This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’.

http://rstb.royalsocietypublishing.org/content/371/1703#articles

Monoy et al. Temporal changes in tree species and trait composition in a cyclone-prone Pacific dipterocarp forest. Ecosystems. 

http://link.springer.com/article/10.1007/s10021-016-9983-0/fulltext.html

Abstract: Our understanding of the effects of tropical cyclones on species composition and dynamics of forest communities is mainly derived from studies that have considered single cyclonic events. Here we examined changes in the tree species and functional trait composition in an 8-ha Dipterocarp forest at Palanan in the northeastern Philippines that is subject to a high frequency of cyclonic disturbance (1–4 cyclones annually). The plot has been censused four times over a 16-year interval allowing us to consider the medium-term forest dynamics in response to repeated cyclones. We hypothesized that as the forest community in Palanan has been selected under frequent disturbance by cyclones, it should show little functional change across the census intervals. We analyzed changes in demography, species composition, and community-weighted functional traits (specific leaf area, leaf area, wood density, and specific growth rate) across the censuses and compared these against cyclone intensities during the census intervals. Demographic changes across census years suggest that the community responded to cyclonic disturbances through substantial turnover in the small- and medium-size individuals, and that there has been an increase in plot-level stem density and basal area across the measured period. Trait compositional changes from 1994 to 2010 were mostly small, but indicate a shift towards species with larger leaves and faster growth rates—traits that are associated with fast recovery after disturbance. These changes all coincide with a large intense cyclone between the second and third censuses, suggesting that cyclone strength, more than cyclone frequency, affects this forest.